/*
 * libwebsockets - small server side websockets and web server implementation
 *
 * Copyright (C) 2010 Andy Green <andy@warmcat.com>
 *
 *  This library is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Lesser General Public
 *  License as published by the Free Software Foundation:
 *  version 2.1 of the License.
 *
 *  This library is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 *  Lesser General Public License for more details.
 *
 *  You should have received a copy of the GNU Lesser General Public
 *  License along with this library; if not, write to the Free Software
 *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
 *  MA  02110-1301  USA
 */

#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <strings.h>
#include <ctype.h>
#include <errno.h>
#include <fcntl.h>
#include <signal.h>

#ifdef __cplusplus
	extern "C" {
		#include <cstddef>
	#endif
		#ifdef  __MINGW64__
		#else
		#ifdef  __MINGW32__
		#else
		#include <netdb.h>
		#endif
		#endif
		#include <stdarg.h>

		#include <sys/stat.h>

		#ifdef WIN32
		#ifdef  __MINGW64__
		#else
		#ifdef  __MINGW32__
		#else
		#include <time.h >
		#endif
		#endif
		#include <winsock2.h>
		#include <ws2ipdef.h>
		#include <windows.h>

		#else

		#include <sys/types.h>
		#include <sys/socket.h>
		#ifndef LWS_NO_FORK
		#ifdef HAVE_SYS_PRCTL_H
		#include <sys/prctl.h>
		#endif
		#endif
		#include <netinet/in.h>
		#include <netinet/tcp.h>
		#include <arpa/inet.h>

		#include <poll.h>
		#include <sys/mman.h>
		#include <sys/time.h>

		#endif

		#ifdef LWS_OPENSSL_SUPPORT
		#include <openssl/ssl.h>
		#include <openssl/evp.h>
		#include <openssl/err.h>
		#include <openssl/md5.h>
		#include <openssl/sha.h>
		#endif


		#include "libwebsockets.h"

		#if 0
		#define DEBUG
		#endif

		#ifdef DEBUG
		#ifdef WIN32
		static
		#else
		static inline
		#endif
		void debug(const char *format, ...)
		{
			va_list ap;
			va_start(ap, format); vfprintf(stderr, format, ap); va_end(ap);
		}
		#else
		#ifdef WIN32
		static
		#else
		static inline
		#endif
		void debug(const char *format, ...)
		{
		}
		#endif


		/*
		 * Mac OSX as well as iOS do not define the MSG_NOSIGNAL flag,
		 * but happily have something equivalent in the SO_NOSIGPIPE flag.
		 */
		#ifdef __APPLE__
		#define MSG_NOSIGNAL SO_NOSIGPIPE
		#endif


		#define FD_HASHTABLE_MODULUS 32
		#define MAX_CLIENTS 100
		#define LWS_MAX_HEADER_NAME_LENGTH 64
		#define LWS_MAX_HEADER_LEN 4096
		#define LWS_INITIAL_HDR_ALLOC 256
		#define LWS_ADDITIONAL_HDR_ALLOC 64
		#define MAX_USER_RX_BUFFER 4096
		#define MAX_BROADCAST_PAYLOAD 2048
		#define LWS_MAX_PROTOCOLS 10
		#define LWS_MAX_EXTENSIONS_ACTIVE 10
		#define SPEC_LATEST_SUPPORTED 13

		#define MAX_WEBSOCKET_04_KEY_LEN 128
		#define SYSTEM_RANDOM_FILEPATH "/dev/urandom"

		enum lws_websocket_opcodes_04 {
			LWS_WS_OPCODE_04__CONTINUATION = 0,
			LWS_WS_OPCODE_04__CLOSE = 1,
			LWS_WS_OPCODE_04__PING = 2,
			LWS_WS_OPCODE_04__PONG = 3,
			LWS_WS_OPCODE_04__TEXT_FRAME = 4,
			LWS_WS_OPCODE_04__BINARY_FRAME = 5,

			LWS_WS_OPCODE_04__RESERVED_6 = 6,
			LWS_WS_OPCODE_04__RESERVED_7 = 7,
			LWS_WS_OPCODE_04__RESERVED_8 = 8,
			LWS_WS_OPCODE_04__RESERVED_9 = 9,
			LWS_WS_OPCODE_04__RESERVED_A = 0xa,
			LWS_WS_OPCODE_04__RESERVED_B = 0xb,
			LWS_WS_OPCODE_04__RESERVED_C = 0xc,
			LWS_WS_OPCODE_04__RESERVED_D = 0xd,
			LWS_WS_OPCODE_04__RESERVED_E = 0xe,
			LWS_WS_OPCODE_04__RESERVED_F = 0xf,
		};

		enum lws_websocket_opcodes_07 {
			LWS_WS_OPCODE_07__CONTINUATION = 0,
			LWS_WS_OPCODE_07__TEXT_FRAME = 1,
			LWS_WS_OPCODE_07__BINARY_FRAME = 2,

			LWS_WS_OPCODE_07__NOSPEC__MUX = 7,

			/* control extensions 8+ */

			LWS_WS_OPCODE_07__CLOSE = 8,
			LWS_WS_OPCODE_07__PING = 9,
			LWS_WS_OPCODE_07__PONG = 0xa,
		};


		enum lws_connection_states {
			WSI_STATE_HTTP,
			WSI_STATE_HTTP_HEADERS,
			WSI_STATE_DEAD_SOCKET,
			WSI_STATE_ESTABLISHED,
			WSI_STATE_CLIENT_UNCONNECTED,
			WSI_STATE_RETURNED_CLOSE_ALREADY,
			WSI_STATE_AWAITING_CLOSE_ACK,
		};

		enum lws_rx_parse_state {
			LWS_RXPS_NEW,

			LWS_RXPS_SEEN_76_FF,
			LWS_RXPS_PULLING_76_LENGTH,
			LWS_RXPS_EAT_UNTIL_76_FF,

			LWS_RXPS_04_MASK_NONCE_1,
			LWS_RXPS_04_MASK_NONCE_2,
			LWS_RXPS_04_MASK_NONCE_3,

			LWS_RXPS_04_FRAME_HDR_1,
			LWS_RXPS_04_FRAME_HDR_LEN,
			LWS_RXPS_04_FRAME_HDR_LEN16_2,
			LWS_RXPS_04_FRAME_HDR_LEN16_1,
			LWS_RXPS_04_FRAME_HDR_LEN64_8,
			LWS_RXPS_04_FRAME_HDR_LEN64_7,
			LWS_RXPS_04_FRAME_HDR_LEN64_6,
			LWS_RXPS_04_FRAME_HDR_LEN64_5,
			LWS_RXPS_04_FRAME_HDR_LEN64_4,
			LWS_RXPS_04_FRAME_HDR_LEN64_3,
			LWS_RXPS_04_FRAME_HDR_LEN64_2,
			LWS_RXPS_04_FRAME_HDR_LEN64_1,

			LWS_RXPS_07_COLLECT_FRAME_KEY_1,
			LWS_RXPS_07_COLLECT_FRAME_KEY_2,
			LWS_RXPS_07_COLLECT_FRAME_KEY_3,
			LWS_RXPS_07_COLLECT_FRAME_KEY_4,

			LWS_RXPS_PAYLOAD_UNTIL_LENGTH_EXHAUSTED
		};


		enum connection_mode {
			LWS_CONNMODE_WS_SERVING,
			LWS_CONNMODE_WS_CLIENT,

			/* transient modes */
			LWS_CONNMODE_WS_CLIENT_WAITING_PROXY_REPLY,
			LWS_CONNMODE_WS_CLIENT_ISSUE_HANDSHAKE,
			LWS_CONNMODE_WS_CLIENT_WAITING_SERVER_REPLY,
			LWS_CONNMODE_WS_CLIENT_WAITING_EXTENSION_CONNECT,
			LWS_CONNMODE_WS_CLIENT_PENDING_CANDIDATE_CHILD,

			/* special internal types */
			LWS_CONNMODE_SERVER_LISTENER,
			LWS_CONNMODE_BROADCAST_PROXY_LISTENER,
			LWS_CONNMODE_BROADCAST_PROXY
		};


		#define LWS_FD_HASH(fd) ((fd ^ (fd >> 8) ^ (fd >> 16)) % FD_HASHTABLE_MODULUS)

		struct libwebsocket_fd_hashtable {
			struct libwebsocket *wsi[MAX_CLIENTS + 1];
			int length;
		};

		struct libwebsocket_protocols;

		struct libwebsocket_context {
			struct libwebsocket_fd_hashtable fd_hashtable[FD_HASHTABLE_MODULUS];
			struct pollfd fds[MAX_CLIENTS * FD_HASHTABLE_MODULUS + 1];
			int fds_count;
			int listen_port;
			char http_proxy_address[256];
			char canonical_hostname[1024];
			unsigned int http_proxy_port;
			unsigned int options;
			unsigned long last_timeout_check_s;

			int fd_random;

		#ifdef LWS_OPENSSL_SUPPORT
			int use_ssl;
			SSL_CTX *ssl_ctx;
			SSL_CTX *ssl_client_ctx;
		#endif
			struct libwebsocket_protocols *protocols;
			int count_protocols;
			struct libwebsocket_extension *extensions;

			void *user_space;
		};


		enum pending_timeout {
			NO_PENDING_TIMEOUT = 0,
			PENDING_TIMEOUT_AWAITING_PROXY_RESPONSE,
			PENDING_TIMEOUT_ESTABLISH_WITH_SERVER,
			PENDING_TIMEOUT_AWAITING_SERVER_RESPONSE,
			PENDING_TIMEOUT_AWAITING_PING,
			PENDING_TIMEOUT_CLOSE_ACK,
			PENDING_TIMEOUT_AWAITING_EXTENSION_CONNECT_RESPONSE,
		};


		/*
		 * This is totally opaque to code using the library.  It's exported as a
		 * forward-reference pointer-only declaration; the user can use the pointer with
		 * other APIs to get information out of it.
		 */

		struct libwebsocket {
			const struct libwebsocket_protocols *protocol;
			struct libwebsocket_extension *
						   active_extensions[LWS_MAX_EXTENSIONS_ACTIVE];
			void *active_extensions_user[LWS_MAX_EXTENSIONS_ACTIVE];
			int count_active_extensions;

			enum lws_connection_states state;

			char name_buffer[LWS_MAX_HEADER_NAME_LENGTH];
			int name_buffer_pos;
			int current_alloc_len;
			enum lws_token_indexes parser_state;
			struct lws_tokens utf8_token[WSI_TOKEN_COUNT];
			int ietf_spec_revision;
			char rx_user_buffer[LWS_SEND_BUFFER_PRE_PADDING + MAX_USER_RX_BUFFER +
								  LWS_SEND_BUFFER_POST_PADDING];
			int rx_user_buffer_head;
			enum libwebsocket_write_protocol rx_frame_type;
			int protocol_index_for_broadcast_proxy;
			enum pending_timeout pending_timeout;
			unsigned long pending_timeout_limit;

			int sock;

			enum lws_rx_parse_state lws_rx_parse_state;
			char extension_data_pending;
			struct libwebsocket *candidate_children_list;
			struct libwebsocket *extension_handles;

			/* 04 protocol specific */

			char key_b64[150];
			unsigned char masking_key_04[20];
			unsigned char frame_masking_nonce_04[4];
			unsigned char frame_mask_04[20];
			unsigned char frame_mask_index;
			size_t rx_packet_length;
			unsigned char opcode;
			unsigned char final;

			int pings_vs_pongs;
			unsigned char (*xor_mask)(struct libwebsocket *, unsigned char);
			char all_zero_nonce;

			enum lws_close_status close_reason;

			/* 07 specific */
			char this_frame_masked;

			/* client support */
			char initial_handshake_hash_base64[30];
			enum connection_mode mode;
			char *c_path;
			char *c_host;
			char *c_origin;
			char *c_protocol;
			callback_function *c_callback;

			char *c_address;
			int c_port;


		#ifdef LWS_OPENSSL_SUPPORT
			SSL *ssl;
			BIO *client_bio;
			int use_ssl;
		#endif

			void *user_space;
		};

		extern int
		libwebsocket_client_rx_sm(struct libwebsocket *wsi, unsigned char c);

		extern int
		libwebsocket_parse(struct libwebsocket *wsi, unsigned char c);

		extern int
		libwebsocket_interpret_incoming_packet(struct libwebsocket *wsi,
								unsigned char *buf, size_t len);

		extern int
		libwebsocket_read(struct libwebsocket_context *context,
						struct libwebsocket *wsi,
								   unsigned char *buf, size_t len);

		extern int
		lws_b64_selftest(void);

		extern unsigned char
		xor_no_mask(struct libwebsocket *wsi, unsigned char c);

		extern unsigned char
		xor_mask_04(struct libwebsocket *wsi, unsigned char c);

		extern unsigned char
		xor_mask_05(struct libwebsocket *wsi, unsigned char c);

		extern struct libwebsocket *
		wsi_from_fd(struct libwebsocket_context *context, int fd);

		extern int
		insert_wsi(struct libwebsocket_context *context, struct libwebsocket *wsi);

		extern int
		delete_from_fd(struct libwebsocket_context *context, int fd);

		extern void
		libwebsocket_set_timeout(struct libwebsocket *wsi,
							 enum pending_timeout reason, int secs);

		extern int
		lws_issue_raw(struct libwebsocket *wsi, unsigned char *buf, size_t len);


		extern void
		libwebsocket_service_timeout_check(struct libwebsocket_context *context,
							struct libwebsocket *wsi, unsigned int sec);

		extern struct libwebsocket *
		__libwebsocket_client_connect_2(struct libwebsocket_context *context,
			struct libwebsocket *wsi);

		extern struct libwebsocket *
		libwebsocket_create_new_server_wsi(struct libwebsocket_context *context);

		extern char *
		libwebsockets_generate_client_handshake(struct libwebsocket_context *context,
				struct libwebsocket *wsi, char *pkt);

		extern int
		lws_handle_POLLOUT_event(struct libwebsocket_context *context,
						  struct libwebsocket *wsi, struct pollfd *pollfd);

		extern int
		lws_any_extension_handled(struct libwebsocket_context *context,
					  struct libwebsocket *wsi,
					  enum libwebsocket_extension_callback_reasons r,
					  void *v, size_t len);

		extern void *
		lws_get_extension_user_matching_ext(struct libwebsocket *wsi,
					  struct libwebsocket_extension *ext);

		extern int
		lws_client_interpret_server_handshake(struct libwebsocket_context *context,
				struct libwebsocket *wsi);

		extern int
		libwebsocket_rx_sm(struct libwebsocket *wsi, unsigned char c);

		extern int
		lws_issue_raw_ext_access(struct libwebsocket *wsi,
								char *buf, size_t len);

		#ifndef LWS_OPENSSL_SUPPORT

		unsigned char *
		SHA1(const unsigned char *d, size_t n, unsigned char *md);

		void
		MD5(const unsigned char *input, int ilen, unsigned char *output);

		#endif

#ifdef __cplusplus
	}
#endif
